Sending with SSL on port 465 there is a connection problem. I have got the following fronm the server
xxxx did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA
and
rejecting commands from xxxx due to pre-greeting traffic

I manage the mail server the latter is due to the client not waiting for responses from the server in the SMTP dialog.

Without using SSL and using port 25 there is no problem sending emails.

The server requires authentication of the sender prior to accepting out bound emails.